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    <h1 align="center">Instructions for image quality evaluation</h1>
    <h2>Introduction</h2>
    <p>Your task is to evaluate the subjective quality of images. Each HIT can be completed in around 60 seconds.</p>

    <h2>Payment</h2>
    <p>We have methods that analyze the consistency of your answers with respect to themselves, to those of your fellow workers and to references we know to be accurate. We will use these methods to rank the submitted assignments according to quality.
    <p>For this experiment we will pay a base reward of $0.10/HIT for every accepted HIT. We have made available a set of 10 different HITs. You will receive a bonus of:</p>
    <ul>
      <li>$0.05/HIT (for a total of $0.15/HIT) if you submit all 10 HITs or</li>
      <li>$0.10/HIT (for a total of $0.20/HIT) if you submit all 10 HITs and your results are among the top 50% or</li>
      <li>$0.15/HIT (for a total of $0.25/HIT) if you submit all 10 HITs and your results are among the top 10%.</li>
    </ul>

    <p>Bonuses will be paid up to 7 days after submission, because we can only rank the submissions once we have a statistically significant number of answers. The base reward will always be paid within 24 hours of submission.</p>

    <h2>Instructions</h2>
    <p>Each file should be given a score according to the following scale, known as the MOS (mean opinion score) scale:</p>

      <table>
        <tbody>
          <tr>
            <td align="center" width="100"><b>Score</b></td>
            <td width="200"><b>Quality</b></td>
            <td width="300"><b>Impairment</b></td>
          </tr>
          <tr>
            <td align="center">5</td>
            <td>Excellent</td>
            <td>Imperceptible</td>
          </tr>
          <tr>
            <td align="center">4</td>
            <td>Good</td>
            <td>Just perceptible, but not annoying</td>
          </tr>
          <tr>
            <td align="center">3</td>
            <td>Fair</td>
            <td>Perceptible and slightly annoying</td>
          </tr>
          <tr>
            <td align="center">2</td>
            <td>Poor</td>
            <td>Annoying, but not objectionable</td>
          </tr>
          <tr>
            <td align="center">1</td>
            <td>Bad</td>
	    <td>Very annoying and objectionable</td>
          </tr>
        </tbody>
      </table>

      <p>The following references illustrate the meaning of each score. Please note that you may encounter other types of distortions. Therefore, these examples do not exhaust the range of conditions you can expect to see.</p>

      <h2>Examples</h2>
      <center>
      <div class="picture left">
        <img src="lena90.jpg" border="0"><br/>
        Reference score: <b>4.0</b><br/>
	The score is not 5.0 because the photo is somewhat noisy and blurry
      </div>

      <div class="picture left">
        <img src="lena15.jpg" border="0"><br/>
        Reference score: <b>3.0</b><br/>
	In addition to being blurry, this photo shows some distortion
      </div>

      <div class="picture left">
        <img src="lena05.jpg" border="0"><br/>
        Reference score: <b>2.0</b><br/>
	This photo has noticeable block effects
      </div>

      <div class="picture left">
        <img src="lena01.jpg" border="0"><br/>
	Reference score: <b>1.5</b><br/>
	This photo has very strong block effects
      </div>
      </center>

      <div style="clear: both;">
      <h2>Approval/Rejection Policy</h2>
      <p>Your results will be collected and evaluated for consistency. We (the requesters) have an estimate of each file's subjective quality that conforms with the references above. Thus, we can detect if someone submits random scores or does not rate according to these instructions, which can lead to work being rejected. You can rest assured that your work will be approved if you rate according to the table and examples above.</p>
      <p>Answers will be either reviewed or automatically approved within 24 hours.</p>
      </div>

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